title: Analysis of aortic wall stress and rupture risk in patients with abdominal aortic aneurysm with a gender perspective.
abstract: OBJECTIVE
  The most commonly used predictor of rupture of an abdominal aortic aneurysm (AAA) is the diameter; however, this does not estimate the true risk for each patient. Why women with AAAs have an increased growth rate, weaker aortic wall, and increased risk for rupture is yet unclear. It is likely that geometrical and biomechanical properties contribute to found gender differences. Several studies have shown that peak wall stress (PWS) and peak wall rupture risk (PWRR), predicted by a finite element (FE) analysis of AAAs derived from computed tomography (CT), is a better predictor of rupture than maximum diameter. The purpose of this study was to investigate if women with AAAs have an increased PWS and PWRR using an FE model compared to men.
  
  
  METHODS
  Fifteen men and 15 women (AAAs 4-6 cm) were included. AAA geometry was derived from CT scans, and PWS and PWRR were estimated using the FE method. Comparisons were made by t test and Mann-Whitney test.
  
  
  RESULTS
  Mean age (women 73 years old vs men 71 years old) and mean AAA diameter was similar (49.7 mm vs 50.1 mm) for women and men. PWS did not differ for women 184 and men 198 kPa. PWRR was 0.54 (0.28-0.85) for women and 0.43 (0.24-0.66) for men, P = .06.
  
  
  CONCLUSIONS
  This is the first analysis of stress and strength of the aneurysm wall with a gender perspective. The reported higher rupture risk for women has previously not been tested with geometrical and biomechanical properties. PWS did not differ, but the PWRR was slightly higher in women. However, the difference did not reach statistical significance, probably due to the small sample size. In summary, the results in the present study suggest that differences in biomechanical properties could be a contributing explanation for the higher rupture risk reported for female patients with AAAs.
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden. emma.larsson@ki.se
authors.forename: Emma
authors.initials: E
authors.lastname: Larsson
authors.forename: Fausto
authors.initials: F
authors.lastname: Labruto
authors.forename: T Christian
authors.initials: TC
authors.lastname: Gasser
authors.forename: Jesper
authors.initials: J
authors.lastname: Swedenborg
authors.forename: Rebecka
authors.initials: R
authors.lastname: Hultgren
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging / Q000503:physiopathology*; D017544:Aortic Aneurysm, Abdominal / Q000150:complications* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001019:Aortic Rupture / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D001027:Aortography / Q000379:methods; D001696:Biomechanical Phenomena; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D013314:Stress, Mechanical; D013548:Sweden; D014057:Tomography, X-Ray Computed